This invention relates to foods, and more particularly to food formed by modification of proteins.
Protein deficiency is common throughout many parts of the world, with protein malnutrition being the most wide spread and serious nutritional problem in the underdeveloped areas of the world. Health problems resulting from protein deficiency have not yet been solved because the remedies available are not multi-purpose and inexpensive. A solution suitable for one country may not be acceptable for another because of economic resources, climate, social patterns, eating habits and ethnic limitations. Worldwide research to develop protein rich foods of low cost has been the most important attempt to prevent protein malnutrition.
Present economic conditions, which result in high cost for food, lead to research in how to make essential nutrients more available to the general public at a lower cost. Meat is one of the most popular contributors of high quality protein, and other nutrients to the American diet. However, rising beef prices bring out the realization that it is now necessary to seek new and less expensive protein sources. There are many sources of protein available. Besides meat, other animal proteins are poultry, fish, eggs, milk and milk products. Soybeans, peanuts, cereals and other plant or vegetable proteins are the other major protein sources. However, many of these plant proteins lack the required palatability to make them suitable for use. Various methods of modification of these protein sources are being used to make them more palatable and therefore more acceptable. However, the present processes of modifying the alternative protein sources have not provided the desired cost effectiveness reduction or palatability to render the material suitable as a substitute.
One such substitute protein is basically known as texturized protein. There are three basic processes for forming this texturized protein. There is a spinning process, an extrusion process, and a glass-puffing extrusion process. The spinning process involves extruding a protein dope or solution through a die into a coagulation bath to form fibers. The problem becomes obvious during the extrusion of the dope and the determination of a proper coagulation bath. In the extrusion process, high pressures and temperatures are used to form a plexilaminate. In this product the cells of the product are longer in the direction of the extrusion. The glass-puffing process is also a high pressure and high temperature process. The use of high pressure and high temperature requires sophisticated, expensive equipment, capital, and skills to handle. The high temperature and pressure also damages the protein thus processed. Furthermore, the protein thus being processed still retains some of its undesirable flavor and taste characteristics. For example, the taste of the protein has not been improved. The type of protein being processed may well not have the desired palatability. Thus, while there exist processes for forming suitable protein substitutes, many problems still remain to be solved in the formation of protein substitutes.
In the prior art spun protein processes, there is an effluent disposal problem. This effluent results from the basic nature of prior art wet processes. In order to treat the raw protein, the raw material is dissolved in an alkali medium. For example, soy protein isolate can be dissolved in sodium hydroxide solution to form a protein dope. This solution of protein is then extruded into an acid coagulation bath. This acid bath coagulates the protein, and the protein fibers are formed. The fibers thus formed are tender and must be hardened in a salt solution bath to make them suitable for use. Thus, there are three basic steps in the prior art for forming spun protein fibers. In each of the three basic steps a liquid residue is left after the process is complete. It becomes a problem to dispose of these residues.
In an effort to improve the texture of protein and avoid the effluent problem, sheeting technology provides an appropriate answer. Presently with this sheeting technology it is necessary to use high pressure. Such high pressure is difficult to handle and complicates the process of sheeting the protein. Furthermore, the high pressure does not always produce a desirable protein. Substantial modification to the protein sheet formed under high pressure is usually required to make a suitable product. Creping is one modification. Even that creping requires substantial further treatment to achieve a textured meat-like product. That treatment is substantial and adds to the cost of the product without achieving all of the desired features of textured product.
Thus, the modification of protein to render it suitable for use in a variety of ways has caused a substantial number of problems in the prior art. These problems remain to be solved.